The present invention relates to a method for the treatment of a disease state associated with angiogenesis by the administration of an anti-angiogenic agent and an anti-hypertensive agent, to a pharmaceutical composition comprising an anti-angiogenic agent and an anti-hypertensive agent, to a kit comprising an anti-angiogenic agent and an anti-hypertensive agent, and to the use of an anti-angiogenic agent and an anti-hypertensive agent in the manufacture of a medicament for use in the production of an anti-angiogenic effect in warm-blooded animals, such as humans.
Angiogenesis, the process of forming new blood vessels, plays an important role in a variety of normal processes including embryonic development, wound healing and several components of female reproductive function. However, undesirable or pathological angiogenesis has been associated with a number of disease states including diabetic retinopathy, psoriasis, cancer, rheumatoid arthritis, atheroma, Kaposi's sarcoma and haemangioma (Fan et al, 1995, Trends Pharmacol. Sci. 16: 57-66; Folkman, 1995, Nature Medicine 1: 27-31).
Angiogenesis is stimulated via the promotion of the growth of endothelial cells. Several polypeptides with in vitro endothelial cell growth promoting activity have been identified including, acidic and basic fibroblast growth factors (aFGF & bFGF) and vascular endothelial growth factor (VEGF). The growth factor activity of VEGF, in contrast to that of the FGFs, is relatively specific towards endothelial cells, by virtue of the restricted expression of its receptors. Recent evidence indicates that VEGF is an important stimulator of both normal and pathological angiogenesis (Jakeman et al, 1993, Endocrinology, 133: 848-859; Kolch et al, 1995, Breast Cancer Research and Treatment, 36:139-155) and vascular permeability (Connolly et al, 1989, J. Biol. Chem. 264: 20017-20024). Alteration of vascular permeability is also thought to play a role in both normal and pathological physiological processes (Cullinan-Bove et al, 1993, Endocrinology 133: 829-837; Senger et al, 1993, Cancer and Metastasis Reviews, 12: 303-324).
Thus antagonism of the activity of VEGF is expected to be beneficial in a number of disease states, associated with angiogenesis and/or increased vascular permeability, such as cancer, diabetes, psoriasis, rheumatoid arthritis, Kaposi's sarcoma, haemangioma, acute and chronic nephropathies, atheroma, arterial restenosis, autoimmune diseases, acute inflammation, excessive scar formation and adhesions, endometriosis, dysfunctional uterine bleeding and ocular diseases with retinal vessel proliferation. For example, antagonism of VEGF action by sequestration of VEGF with antibody can result in inhibition of tumour growth (Kim et al, 1993, Nature 362: 841-844).
VEGF binds to a receptor with intrinsic tyrosine kinase activity, a so-called receptor tyrosine kinase (RTK). RTKs are important in the transmission of biochemical signals across the plasma membrane of cells. These transmembrane molecules characteristically consist of an extracellular ligand-binding domain connected through a segment in the plasma membrane to an intracellular tyrosine kinase domain. Binding of ligand to the receptor results in stimulation of the receptor-associated tyrosine kinase activity which leads to phosphorylation of tyrosine residues on both the receptor and other intracellular molecules. These changes in tyrosine phosphorylation initiate a signalling cascade leading to a variety of cellular responses. To date, at least nineteen distinct RTK subfamilies, defined by amino acid sequence homology, have been identified. One of these subfamilies is presently comprised by the fms-like tyrosine kinase receptor, Flt or Flt1, the kinase insert domain-containing receptor, KDR (also referred to as Flk-1), and another fms-like tyrosine kinase receptor, Flt4. Two of these related RTKs, Flt and KDR, have been shown to bind VEGF with high affinity (De-Vries et al, 1992, Science 255: 989-991; Terman et al, 1992, Biochem. Biophys. Res. Comm. 1992, 187: 1579-1586). Binding of VEGF to these receptors expressed in heterologous cells has been associated with changes in the tyrosine phosphorylation status of cellular proteins and calcium fluxes.
Compounds which are inhibitors of VEGF receptor tyrosine kinase are described, for example in, International Patent Applications Publication Nos. WO 97/22596, WO 97/30035, WO 97/32856, WO 97/34876, WO 97/42187, WO 98/13354, WO 98/13350, WO 99/10349, WO 00/21955 and WO 00/47212.
In the normal mammal blood pressure is strictly controlled. This is facilitated by a complex interaction of a number of mediators, whose effects are maintained at an equilibrium. The system is such that if the level of one mediator changes this is compensated for by the other mediators such that normal blood pressure is maintained. (for a review of the systems which maintain blood pressure the reader is referred to: Guyton et al 1972 Annual Review of Physiology 34, 13-46; and Quan et al 1997 Pacing and Clinical Electrophysiology 20, 764-774). It is important that blood pressure is tightly controlled because hypertension, high blood pressure, underlies a variety of cardiovascular diseases, such as stroke, acute myocardial infarction, and renal failure.
A number of substances exhibit effects on blood vessels in vitro which in isolation would suggest effects on blood pressure in vivo. However, because of the nature of the control of blood pressure often any effects in vivo are compensated for and thus normal blood pressure is maintained.
It has been reported that VEGF and FGF have acute effects on vascular tone. VEGF has been shown to dilate coronary arteries in the dog in vitro (Ku et. al., 1993, Am J Physiol 265:H585-H592) and to induce hypotension in the conscious rat (Yang et. al., 1996, J Cardiovasc Pharmacol 27:838-844). However, in vivo these effects are only transitory. Even with a very large dose of VEGF (250 μg/kg) in conscious rats Yang et al observed a return to normal blood pressure within 20 minutes, at lower doses blood pressure returned to normal significantly faster. Boussairi et. al. have observed a similar effect upon administration of bFGF to anaesthetised rats, with the blood pressure returning to normal within 30 minutes after addition of 15 μg/kg bFGF (J Cardiovasc Pharmacol 1994 23:99-102). These studies also show that tachyphylaxis (or desensitisation) quickly develops following growth factor administration. Thus further administration of growth factor has no effect on blood pressure.
It has been reported that the vasodilation induced by both FGF and VEGF depends, at least in part, on the release of nitric oxide (NO), also referred to as endothelially derived relaxant factor (EDRF), (Morbidelli et. al., 1996, Am J Physiol 270:H411-H415 and Wu et. al., 1996, Am J Physiol 271:H1087-H1093).
In International Patent Application Publication No. WO 98/28006 a method for treating a hypertensive disorder in a pregnant woman is described, the method comprising administering to the pregnant woman an amount of a therapeutic substance which regulates the amount, and/or activity of, VEGF. In International Patent Application Publication No. WO 00/13703 is described a method for treating hypertension comprising administering to a patient an effective amount of an angiogenic factor such as VEGF, or an agonist thereof.